Safety push button knife



9- 7 E. J. CONKLIN 2,183,373

SAFETY PUSH BUTTON KNIFE Filed Ma 18, 1958 v u 48 v l s5 35 in 37 53% 2' Flag INVE OR BY F25 2? Patented Dec. 12, 1939 UNITED STATES PATENT OFFICE 10 Claims.

This invention relates to pocket knives of the safety push button type, and has for an object to provide a simple and effective means of looking the blade either in the closed or open posi- 6 tion, and in which it will be diificult to inadvertently release the locking means, and thus provide a real safety push button knife.

It is also an object to provide such a safety feature which in normal operation will be auto- 10 matically held in and returned to the locking position with ordinary movements from this position, but may be moved to the full released position and remain there for easy and convenient use of the knife.

It is another object of the invention to provide these safety features Without adding extra parts to the constructions of push button knives now commonly used, and thus effect the safety features without increasing the cost of manu- 20 facture.

With the foregoing and other objects in View I have devised an improved construction several embodiments of which are illustrated in the accompanying drawing forming a part of this speci- 5 fication, it being understood that various changes and modifications may be employed within the scope of the invention.

'In this drawing: 7

Fig. 1 is a plan view of one end portion of a 30 push button knife embodying my improved construction with the cheek plate removed;

Fig. 2 is a longitudinal section thereof substantially on line 22 of Fig. 1 but showing the cheek plate in position;

35 Fig. 3 is a top plan view of Fig. 2;

Fig. 4 is a transverse section substantially on line 4-4 of Fig. 2;

Figs. 5 and 6 are a top plan View and side elevation respectively of the safety slide;

Figs. 6a and6b are a top and side View respectively of one end portion of the lock spring;

Fig. 7 is a plan view of one end of the lining plate;

Fig. 8 is a side elevation thereof showing a 45 safety slide thereon in the released position;

Fig. 9 is a view similar to Fig. 1 of the so-called safety push button dagger showing a modified construction;

Fig. 10 is a longitudinal section substantially 55 plate of the construction of Figs. 9 and stantially on line I'l-I'I of Fig. 16; 10"

Figs. 18 and 19 are a top plan and side View respectively of the safety slide used in the construction of Figs. 16 and 1'7; and

Figs. 20 and 21are a top plan and side view respectively of a portion of the liner plate of the construction of Figs. 16 and 17.

Referring first to the type of device shown'in Figs. 1 to 8'inolusive, the knife comprises the usual construction of a push button knife, the push button control being shown for one blade only. It comprises the usual metal lining plates I and 2 between which the blade 3 is pivotedin the usual manner on a transverse rivet or pin 4 passing through the lining plates and the cheek plates 5 and 6. The pivot pin 4 may have a tubular bush- 25 ing 1 on which the blade has its bearing,'and this sleeve may be turned or flanged over at its opposite ends on the lining plates to assist in holding them in position. In Fig. 1 the upper cheek plate 5 is removed showing the operating mechanism in plan view." Mounted in a space between the linings I and 2 is a spring 8 secured in any suitable manner, such for example as being inserted between one of the transverse securing rivets 9 and the spacer back member I0 opened position by means of a locking lever I3 operated to release the blade by means of a push button I4 on the lever extending through an opening in the cheek plate 5 to a position where it may be easily pushed inwardly by a thumb or finger to operate this lever to unlock or release the blade. The blade is locked in the closed position by the opposite end I5 of the lever seating in ,a recess 16 in the topwall of the blade, and the blade is locked in the open position by this end of the lever'l3' seating "in a recess I! located at the opposite side of the pivot 4 from the recess I6. The locking lever I3 is mounted on a pivot pin I8 held at opposite sides of the lever in ears I9 cut and rolled up from the liner I. A flat spring 29 is mounted on the upper surface of the liner I and in a recess 5a in the inner wall of the cheek plate 5 by inserting one end thereof under a lug 2| lanced and struck up from the lining I. The opposite end of this spring indicated at 2| extends under the end of the lever I3 or push button I4 and tends to lift this end of the lever and thus to retain the locking end I5 of the lever against the blade and seat it in one of the notches I 6 or H when in alignment therewith. The locking or safety slide 22 is mounted on the topof the lining I and has a lower spring arm 23 sliding on the top of this lining at one side of the spring 20. The top portion of this slide 22 is wider than the arm 23 as indicated at 24 so as to overhang the spring 20, and carries the finger piece 25 which projects. through an elongated slot 26 in the cheek plate '5 in a position where it may be easily operated to shift the slide 22 to and from the locking position. At one end where the spring arm 23 is joined to the top 24 these members are pinched together, as indicated at 21, so that it may be slid under the laterally extending end portion 2! of the spring 20 as shown in Figs. 1 and 2, so as to prevent depression of "this end of the spring and therefore prevent depression of the button I 4 and operation of the lever I3 to unlock the blade. It will be understood when this slide 22 is shifted to the right as viewed in Figs. 1, 2 and 3 the end 27 will be shifted from under the end 2| of the spring and permit operation of the button I4 by pressing inwardly on this button to raise the opposite end of the lever I3 for the notch in the blade to unlock or release the blade. If the blade is in the closed position when this button is depressed the blade will be thrown to the open position by the spring 8, and the blade will be locked in the open position by the end I5 of the lever I3 seating in the notch IT in the blade.

This construction so far described is old and has been used in pocket knives, but it has a serious objection in that the friction of the spring arm 23 on the lining and the top portion 24 on the cheek is not sufficient to prevent ac- "cidental shifting of the safety slide, either inadvertently while handling the knife, or by rubbing of other articles in the pocket on the finger piece 25, or by rubbing of the material of the pocket itself on this member, so as to shift the -safety slide to the released position, and then pressure on the button I4 in the pocket may release the blade so that it will be thrown to the half open position with the danger of serious injury to one carrying the knife or the liability of severely cutting the hand should it be inserted in the pocket with the knife in this condition.

I have overcome this objection by providing on the lining I in alignment with the free end of the spring arm 23 an inclined tongue 28. This tongue may be conveniently formed by lancing the lining and bending the tongue upwardly. The front wall 29 of this tongue is inclined at a proper angle and is in alignment with the free end of the spring arm 23 so that if the slide 22 is shifted to the right or toward thereleased position the free end of this arm 23 will ride up on the in cline 29. It will be seen thatbecause of the spring action or resiliency of the arm 23 the pressure ofits free end on the inclined surface 29;

will by a camming action on this surface tend to shift the slide 22 to the left or to the locked position with its end 21 under the end 2| of the spring 20 to thus retain the button I 4 and lever I 3 in locked position. Thus any pressure on the finger piece 25 in ordinary handling, or when the knife is carried in the pocket, tending to shift the slide 22 to the right or the released position will be resisted by this camming action, and even if the pressure is sufficient to shift the safety slide somewhat, as soon as this pressure on the finger piece 25 is released this oamming action will immediately and automatically shift the safety slide back to its locking position. It;will be seen that unless some means is provided for holding the safety slide in the fully oif or released position the safety feature would be fully automatic, and on any movement of the slide from the locking position it would be immediately returned to the locking position as soon as pressure causing this movement was released. This would mean that when using the knife the operator would be required to hold the safety slide in the released position while depressing the button It to unlock the blade. This would be rather inconvenient and therefore the parts are so arranged and proportioned that when the safety slide 22 is shifted to the extreme right hand or released position the free end of the spring arm 23 will ride up on to the top of the tongue 29 as shown in dotted lines Fig. 2 and full lines Fig. 8. It will be seen this removes the arm 23 from the inclined surface 29 and therefore there is no camming action tending to shift the safety slide back to the locking position. It will therefore remain in this position for free operation of releasing button I4 until the slide is shifted from this position. A lug or ear 20a (Figs. 1, 2, 6a and 6b) may be cut and bent up from the spring 29 in alignment with the end of the arm 23 to be engaged by the end of this arm and thus form a stop to limit the amount the arm will ride onto the tongue 29.

They parts are so constructed and arranged however that a slight movement of the safety slide to the left or toward the locking position will carry it off the top of the tongue 28, and then cam action on the inclined wall 29 thereof will immediately shift the safety slide to the locking position. This can be made as sensitive as desired by positioning the end of the lug 20a to permit the arm 23 to ride the proper amount onto tongue 29, and it is preferably made so that a slight pressure on or movement of the finger piece 25 will shift it sufliciently to bring the automatic camming action into operation. This will be secured by positioning lug 20a to permit arm 23 to ride only a short distance onto tongue 29. Thus even though the knife may be placed in the pocket with the safety slide in the released position rubbing action of other articles in the pocket or pressure of the material of the pocket itselfwill soon shift the slide sufficiently so that this camming action will automatically shift the slideto the fully locked position. Then as above described ordinary pressures tending to move it in the opposite-directionwill automatically be overcome by the camming action; Thus it will be seen this tongue 28 and arm 23 control the retracting motion of the safety slide 22- so that this slide is held in the locked position until deliberately unlocked,.and any inadvertent pressure on the operating member 25 insufiicient to shift the slide to the fully unlockedapositionwill be counteracted and the slide immediately shiftedbe seen as pointed out above that if it is not v back to the fully locked position as soon as this pressure is removed. This will make a semiautomatic safety push button knife, but it will 30 is somewhat different than that for the smaller type of knife shown in Figs. 1 to'8. The blade is pivoted on the bushing 1 around the transverse rivet or pin 3| in the usual manner and the blade is between the linings 32 and 33. The locking lever 34, instead of being pivoted on a transverse pin in rolled up ears as in the first form, is provided with a transverse notch or groove 35 on its lower side seated on a transverse integral bar 33 left in the lining 32 when the openings 31 and 38 are punched therein. The free end of the lever passes through the opening 38 to seat in the notches 39 and 46 in the blade to lock the blade in either the closed or opened position. The lever'34 carries the push button 4| projecting through an opening in the cheek 42 for operation by the thumb or finger as in the first form. In this construction the safety slide 43' is of resilient spring metal comprising an upper portion 44 carrying the finger piece 45 which projects through an elongated opening 46 in the cheek 42. The slide 43 is reduced in width and bent upon itself as shown at 41 to provide a spring arm 48 extending under the top portion 44. Mounted on the top of the lining 32 is a fiat spring 49 which has an elongated central opening 50 extending for the greater portion of the length of this spring. It is mounted on the lining 32 by inserting the closed portion of this spring at the right hand end of this slot under a tongue cut and raised up from the lining 32. The opposite closed end 52 of the spring rests on top of the locking lever 34 beyond the pivot 36 so as to depress this free end of the lever into the notches in the blade to lock the blade in different positions. The safety slide 43 is mounted with the spring arm 48 within the longitudinal slot 50 in the spring 40 and bearing on top of the lining 32 with the finger To secure the automatic camming action the connection of the tongue 5| to the lining 32 is inclined as shown at 53 corresponding to the incline 29 of the'first form. This incline is in alignment with the free end of the spring arm 48, so that as the safety slide 43 is shifted to the right the free end of this arm 48 rides up on this inclined wall 53 and by the camming action caused by the resiliency of the spring tends to shift the safety slide 43 to the left or to the locked position with its end portion 41 extending under the button 4| and the free end of the lever on which it is mounted. This action is also assisted by the downward inclination of the end portion 41 of the slide. It will be seen this forms an inclined wall 54 on the underside of this end portion, and as this end portion pro-' jects over the edge of the opening 41 into this opening as shown in Fig. it will be seen that movement of the slide 43 to the right will cause a camming action of this inclined wall 54 on the end 55 of the opening 31, which because the resiliency of the slide 43 presses the top portion 44 thereof against the under surface of the cheek 42 tends to shift the slide 43 to the left and retain it in the locked position.

In order to retain this safety slide in the unlocked position the tongue 5| is provided with a short fiat surface 56 at the upper portion of the incline 53 on to which the free end of the arm 48 may slide and rest when the slide 43 is shifted to the right as shown in Fig. 13. This movement to the right may be limited by the free end of the arm 48 engaging a shoulder 51 at the inner end of the flat portion 56. The

operation of this device is the same as that de scribed in connection with the form of Figs. 1 to 8. When the blade is unlocked by depressing the button 4| the spring 36a throws the blade to the open position the same as spring 8 in the first form.

The construction of Figs. 16 to. 21 also operates in the same manner although the parts are constructed and arranged somewhat differently. This construction is usually used with a larger or heavier type of knife. The construction and mounting of the locking lever for the knife blade is the same as that used in Figs. 9.and 10 and therefore the same reference numerals are used for these parts as are used in Figs. 9 and 10. In this construction, however, the mounting tongue 56 for the spring 60 for holding the looking lever 34 in looking position is cut from the lining 6| leaving it attached at one edge, and then it is bent upwardly about this edge to the position shown. The rearward free edge of this tongue is inclined as shown at 62 to form the inclined camming wall corresponding to the inclined walls 29 and 53 of the first two forms. The spring Bil has a longitudinal central slot 63 and the closed right hand end portion ofthe spring is inserted under the hook 64 formed by the tongue 59. The other enclosed end portion 65 rests on top of the lever 34 to the left of the pivot and thus tends to hold the lever in the locking position.

The safety slide 66 is a piece of spring metal bent to substantially U shape as shown in Figs. 18 and 19. The upper portion 61 is reduced in width at the left hand end to form the loop connection 68 and the lower spring arm 66. The top 61 carries the operating finger piece 70. In mounting this slide the arm 69 rests on top of the lining 6|. Within the slot 63 of the spring 66 in the normal locking position shown in full lines Figs. 16. and 17 the looped end 68 lies under the button 4| and retains the lever 34 in the locking position. The inclined surface 62 is in alignment with the end of the spring arm 69 so that when the slide 66 is shifted to the right this arm rides up on the incline 62 and due to the spring or resilient action of the slide has a camming action on this inclined surface to shift the slide to the locked position. The parts are so proportioned that when the slide is shifted to the I 70 projects through an elongated slot H in the cheek T2 for easy operation of. the safety slide. The blade 58 is thrown out to the open position about its pivot 3! when it is released by means of the spring I3 corresponding to the springs 8 and 36a of the other two forms.

It will be seen from the foregoing description that I have devised a construction which greatly increases the safety feature of the knife reducing to a minimum the liability of the blade being inadvertently opened in the pocket or With ordinary handling, and furthermore that I have provided this improved safety feature without adding any additional parts to the knife but have merely changed the shape or provided another tongue on parts already employed in this type of knife. Ihus this improved safety feature adds none or very little extra to the cost of making the knife.

Having thus set forth the nature of. my invention, what I claim is:

1. In a safety knife comprising a pivoted blade, a manually operable locking means for the blade and a shiftable means for holding said first means in looking position including a resilient element, an inclined cam surface cooperating with said resilient element to shift the shiftable means to holding position.

2. In a safety push button knife including a pivoted blade, a locking lever for the blade, a push button for operating the lever, a safety slide movable to and from a position to hold the lever in locking position and including a spring arm, manual means for shifting the slide, and an inclined cam surface cooperating with said spring arm to shift the slide to holding position.

3. In a safety push button knife including a lining plate, a blade pivoted at one side of said plate, a locking lever for the blade pivoted to the plate, a push button for operating the lever, a safety slide shiftable on the plate to and from a position holding the lever in looking position and including a spring arm, and manual means for shifting the slide, a tongue on the plate having an inclined cam surface cooperating with the spring arm to shift the slide to holding position.

4. In a safety push button knife including a lining plate, a blade pivoted at one side of said plate, a locking lever for the blade pivoted to the plate, a push button for operating the lever, a safety slide of resilient metal movable to and from a position to hold the lever in looking position, manual means for shifting the slide, and cooperating camming means on the slide and lining plate to shift the slide to holding position.

5. In a safety push button knife including a pivoted blade, a locking lever for the blade, a push button for operating the lever, a safety slide movable to and from a position to hold the lever in looking position and including a spring arm, manual means for shifting the slide, an inclined cam cooperating with said spring arm to shift the slide to holding position, and said cam having a substantially fiat surface at the top thereof onto which said arm can slide to retain the slide in the released position.

6. In a safety push button knife including a lining plate, a blade pivoted at one side of said plate, a locking lever for the blade pivoted to the plate, a push button for operating the lever, a safety slide shiftable on .the plate to and from a position holding the lever in looking position and including a spring arm, and manual means for shifting the slide, a tongue on the plate having an inclined cam surface cooperating with the spring arm to shift the slide to holding position, and said tongue having a surface at the top of 'the cam onto which the arm can rest to retain the slide in released position.

'7. In a safety push button knife including a lining plate, a blade pivoted at one side of said plate, a locking lever for the blade pivoted to the plate, a push button for operating the lever, a safety slide shiftable on the plate to and from a position holding the lever in looking position, said slide including a top portion and a spring arm extending backwardly under the top portion, manual means for shifting the slide, and a tongue on the plate in alignment with the free end of the arm having an inclined surface cooperating with the free end of the arm to shift the slide to holding position.

8. The knife according to claim 7 in which the tongue has a surface at the top of the inclined surface onto which the free end of the tongue may slide to retain the slide in the released position.

9. In a safety push button knife including a lining plate, a blade pivoted at one side of said plate, a locking lever for the blade pivoted to the plate, a push button for operating the lever, a tongue struck up from the lining, a spring plate mounted on the lining by the tongue and extending under one end of the lever to hold it in looking position, a safety slide mounted on the lining and having an end portion movable to and from a position under the spring to hold the lever in locked position, manual means for shifting the slide, said slide including a spring arm extending under the slide, and a tongue struck up from the lining in alignment with the free end of the arm and having a cam surface cooperating therewith to shift the slide to holding position.

10. In a safety push button knife including a lining plate, a blade pivoted at one side of said plate, a locking lever for the blade pivoted to the plate, a push button for operating the lever, a tongue struck up from the lining, a spring plate mounted on the lining by the tongue and resting at its free end on the lever to hold it in looking position, a safety slide mounted on the lining and movable to and from a position under the lever to retain it in looking position, manual means for shifting the slide, said slide including a spring arm extending under the same, and said tongue having an inclined cam surface cooperating with said arm to shift the slide to holding position.

EDWARD J. CONKLIN. 

